Sheets, elastic exercise bands and tubing are commonly used as a means of providing resistance during exercise, such as during fitness classes and for physical therapy uses. Latex free sheets are also used for clothing, balls, balloons and any areas where rubber characteristics are required. Most of the time bands/tubing are stretched and released a number of times by the body part being worked. For example, a user may hold one end on the band/tube in one hand and stretch and or pull the other half, to work certain muscles.
Commercially available bands/tubing are made from natural rubber latex, and are commonly provided in different resistance levels in order to provide the required resistance level as required for a particular exercise latex sheets/bands are most commonly produced as a cast sheet or a calendared sheet which is then provided in finite lengths or in a continuous roll which can be cut to specific lengths. Latex sheets/bands are also produced similar to latex tubing by an extruding method of allowing a latex material to be pushed through a specific die or by extruding the material through a dog-bone shaped orifice, to form an elongated band having various thicken edges. Both bands and tubing sometimes require handles for the users. One example of exercise equipment based on latex elastic materials is Castellanos U.S. Pat. No. 5,129,647.
The most important concern about the use of latex is the potential for allergy to natural rubber. It has become apparent that contact with latex products can cause an adverse reaction in many individuals. These reactions vary according to the individual and duration and type of latex contact which occurs. As a result, however, many people are required to avoid any and all contact with latex.
Such inability to contact latex products can be of particular disadvantage to healthcare professionals such as physical therapists, who in the normal course of their work are often required to assist their patients in using these resistive exercise devices.
In addition, both latex and thermoplastic elastomers have an unpleasant odor. In order to reduce this unpleasant smell, latex manufacturers are generally forced to provide an odorant in the latex compositions. This is also true of thermoplastic elastomers, which during formulation also use odorants to mask the smell
Thus a need exists for a synthetic material for both bands and tubing to provide the desirable resistance characteristics similar to latex without the undesirable effects of latex. Triolo et al. U.S. Pat. No. 4,089,718 describes a process for making thermoplastic elastomeric articles such as, for example, semi-pneumatic tires, comprising the steps of admixing a thermoplastic, elastomeric molding composition including a vulcanizable or otherwise thermosetable elastomer, inert filler materials, a plasticizer and certain processing aids. The molding composition is then milled into a flat sheet, extruded into a tubular shape, cut, shaped and then molded at a temperature less than about 70° F. into thermoplastic elastomeric articles such as, for example, semi-pneumatic tires. This process has not been found to be suitable for conversion to a method of making exercise bands.
While other methods are used to produce a thermoplastic elastomers sheets/bands, they are generally not suited for a substitute for latex. Thermoplastic elastomers are generally manufactured by dipping or other conventional methods, which includes injection molding. Using this technology, the bands are provided in a seamless, substantially ring-shipped form. This method uses a generally elongated die where the thermoplastic elastomers are then immediately cast onto large cooled rollers to lower the temperatures, add strength and to solidify the material in a form of an elongated continuous film. Using this method results in undesirable side edges, thus the edges must be trimmed to provide a more finished appearance.
One method that has recently been proposed is Williams U.S. Pat. No. 5,945,060, in which A non-allergenic resistive exercise device is described. The device is in the form of a relatively thin elongate band of thermoplastic elastomer. In one embodiment of the invention, the device is in the form of a seamless endless band, while in another, the band is substantially strip-shaped. The bands can be textured to enhance the ability of a user to grip them during use, and the bands can also be printed or otherwise ornamented. The exercise devices of the instant invention are latex-free so as to be non-allergenic, do not require supplemental powdering of their surfaces, and are virtually odor-free. Several methods for producing the bands are also described. In one method, the thermoplastic elastomer material is extruded through an elongate-shaped die to form a cast film, which is solidified and cut to the desired length for use. In this method, the die in desirably substantially dog bone-shaped, in order to produce elongate bands having thickened side edges. In another method, the material is extruded as a hollow tube which is inflated with a gas and enlarged to form a large diameter tube having relatively thin walls. The tube is then cut transversely to form a plurality of seamless, substantially ring-shaped bands.
The problem with the methods of Williams U.S. Pat. No. 5,945,060 is that the materials are formed only with difficulty because they are extruded or cast as films and contain irregularities that prevent the product from having commercially suitable quality.
It would be a great advantage to provide a material that is latex free, has no apparent odor, and can be made into resistive objects in the form of sheets and bands for use as exercise equipment and other uses where latex is not well accepted.
It is therefore an object of this invention to provide an odor free, non latex material and method of forming such a material into sheets for use in a variety of latex replacement uses.
Another object is to provide a non latex material formed into sheets and bands for use as exercise equipment
Still another object is to provide a method of forming the non latex material in predetermined thicknesses.
Yet another object of the present invention is to provide a method for forming the non latex material while incorporating predetermined colors on some or all of the material
Other objects will appear hereinafter.